package vm import ( "math/big" "github.com/ethereum/go-ethereum/ethutil" "github.com/ethereum/go-ethereum/state" ) type ClosureRef interface { ReturnGas(*big.Int, *big.Int) Address() []byte SetCode([]byte) GetStorage(*big.Int) *ethutil.Value SetStorage(*big.Int, *ethutil.Value) } type Closure struct { caller ClosureRef object ClosureRef Code []byte message *state.Message Gas, UsedGas, Price *big.Int Args []byte } // Create a new closure for the given data items func NewClosure(msg *state.Message, caller ClosureRef, object ClosureRef, code []byte, gas, price *big.Int) *Closure { c := &Closure{message: msg, caller: caller, object: object, Code: code, Args: nil} // Gas should be a pointer so it can safely be reduced through the run // This pointer will be off the state transition c.Gas = gas //new(big.Int).Set(gas) // In most cases price and value are pointers to transaction objects // and we don't want the transaction's values to change. c.Price = new(big.Int).Set(price) c.UsedGas = new(big.Int) return c } func (c *Closure) GetValue(x *big.Int) *ethutil.Value { return c.GetRangeValue(x, big.NewInt(1)) } func (c *Closure) GetOp(x int) OpCode { return OpCode(c.GetByte(x)) } func (c *Closure) GetByte(x int) byte { if x > -1 && x < len(c.Code) { return c.Code[x] } return 0 } func (c *Closure) GetBytes(x, y int) []byte { if x >= len(c.Code) || y >= len(c.Code) { return nil } return c.Code[x : x+y] } func (c *Closure) GetRangeValue(x, y *big.Int) *ethutil.Value { if x.Int64() >= int64(len(c.Code)) || y.Int64() >= int64(len(c.Code)) { return ethutil.NewValue(0) } partial := c.Code[x.Int64() : x.Int64()+y.Int64()] return ethutil.NewValue(partial) } /* * State storage functions */ func (c *Closure) SetStorage(x *big.Int, val *ethutil.Value) { c.object.SetStorage(x, val) } func (c *Closure) GetStorage(x *big.Int) *ethutil.Value { m := c.object.GetStorage(x) if m == nil { return ethutil.EmptyValue() } return m } func (c *Closure) Return(ret []byte) []byte { // Return the remaining gas to the caller c.caller.ReturnGas(c.Gas, c.Price) return ret } /* * Gas functions */ func (c *Closure) UseGas(gas *big.Int) bool { if c.Gas.Cmp(gas) < 0 { return false } // Sub the amount of gas from the remaining c.Gas.Sub(c.Gas, gas) c.UsedGas.Add(c.UsedGas, gas) return true } // Implement the caller interface func (c *Closure) ReturnGas(gas, price *big.Int) { // Return the gas to the closure c.Gas.Add(c.Gas, gas) c.UsedGas.Sub(c.UsedGas, gas) } /* * Set / Get */ func (c *Closure) Caller() ClosureRef { return c.caller } func (c *Closure) Address() []byte { return c.object.Address() } func (self *Closure) SetCode(code []byte) { self.Code = code }